Propeller Manual

3: Assembly Language Reference – VSCL
VSCL
Register: Video scale register
DAT
〈Label〉 〈Condition〉 Instruction VSCL, SrcOperand 〈Effects〉
DAT
〈Label〉 〈Condition〉 Instruction DestOperand, VSCL 〈Effects〉
•
Label is an optional statement label. See Common Syntax Elements, page 250.
•
Condition is an optional execution condition. See Common Syntax Elements, page 250.
•
Instruction is the desired assembly instruction. VSCL may be used in either the
assembly instruction’s DestOperand
or SrcOperand fields.
•
SrcOperand is a constant expression used by Instruction to operate on, and optionally
write to, the
VSCL register in DestOperand.
•
DestOperand is a constant expression indicating the register that is operated on, and
optionally written to, using the value of
VSCL in SrcOperand.
Explanation
VSCL is one of two registers (VCFG and VSCL) that affect the behavior of a cog’s Video
Generator. Each cog has a video generator module that facilitates transmitting video image
data at a constant rate. The
VSCL register sets the rate at which video data is generated.
The following code sets the Video Scale register for 160 pixel clocks and 2,560 frame clocks
(for a 16-pixel by 2-bit color frame). Of course, the actual rate at which pixels clock out
depends on the frequency of PLLA in combination with this scale factor.
mov vcfg, VscCfg
VscCfg long %000000000000_10100000_101000000000
See Registers, page 338, and the Spin language VSCL section, page 216, for more information.
Propeller Manual v1.1 · Page 367